Compensating device



March 13, 1956 N E, KLE|N 2,738,141

COMPENSATING DEVICE Fild Dec. 10, 1949 2 Sheets-Sheet 1 44 44 71' 1777","; mm- 4a 'Wwwww mama/64w INVENTOR. NORMQN E. KLEIN E na;-

ATTORNEY March 13, 1956 Filed Dec. 10, 1949 N. E. KLEIN COMPENSATING DEVICE 2 Sheets-Sheet 2 INVENTOR NORMQN E. KLEIN AGENT United States Patent j 2,738,141 COMPENSATING DEVICE Norman E. Klein, Stamford, Conn., assignor to Deering Millikan Research Corporation, Pentlleton, S. (3., a corporation of Delaware Application December 10, 1949, Serial No. 132,226

14 Claims. (Cl. 242--154) The present invention relates to devices for regulating tension, or for compensating for tension variations, and comprises a novel device of this character particularly adapted for use in the textile industry for controlling the tension in a travelling end of yarn.

Rapid and accurate control of the tension in yarn is of paramount importance during numerous operations. both preceding and including the final weaving or knitting of the yarn into fabric. If an acceptable fabric is to be produced, the yarn should not be under too high nor too low a tension during the various operations, nor should the tension therein vary substantially during any one operation. During quill Winding, for example, if the yarn is under too low a tension soft-nosedquills will be produced from which the yarn will slough off during the subsequent weaving operation, while if the yarn is under too high a tension there will be shiners in fabric woven therefrom. Tension variations occurring during one'operation are magnified in succeeding operations and interfere with the efiiciency thereof.

For adequate regulation of yarn tension, a compensating device should be rapid in its response to tensionvari'ations and yet be sufficiently stable so as not to be put into oscillation, and it should not itself introduce a high tension into the yarn. Moreover it should be small and compact, economical to produce, readily adjustable, easy to thread and have along useful life under mill conditions.

Tension compensating devices heretofore suggested or in use in general either have been too sluggish for control of tension in rapidly travelling yarn or have been too large, involving relatively expensive mechanisms cliflicult to maintain in adjustment and having a'tendency to hunt. The device of the present invention, unlike those of the prior art, is small, sensitive but stable, economical to manufacture, simple to adjust and easy to thread.

The new tension compensator comprises essentially two sets of fingers or pins which engage between them an end of yarn during its travel and which, with increase in yarn tension, tend to separate and reduce the angle through which the yarn contacts each pin or finger. A means is provided which tends to oppose separation of the fingers and furnishes the restoring force when the yarn tension decreases. A feature of the device is the construction whereby the torque provided by this means decreases as the fingers are separated from each other with increase in yarn tension.

A further feature of the invention is the construction which permits rapid and easy threading of the yarn between the sets of fingers and betweena pair of tension pads, the pads, in the preferred embodiment of the invention, being provided for introduction of a slight tension into the yarn just prior to its contact with the sets of fingers of the device, the fingers acting as a multiplier of the tension introduced by the pads.

For a better understanding of the invention and of the novel features thereof, reference may be had to the accompanying drawings of which:

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Figs. 1 and 2 are, end and front views respectively of av tension compensator embodying the invention;

Fig. '3 is a vertical sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is a top plan view, partly in section, taken on the line 44 of Fig. 2;

Figs. 5 and 6 are front and end views respectively of another embodiment of tensioncompensator of the invention;

Fig. 7 is a horizontal sectional view taken on the line '77 of Fig. 5; and

Fig. 8 is a view on an enlarged scale of the upper portion of Fig. 5.

In the particular embodiment of the invention illustrated in Figs. 1 to 4 inclusive, one set of pins or fingers is fixed and comprises small plates 2, each of which may be press fit or otherwise secured in a channel 4 in a base member 6 and is cut away and rounded along a part of its upper edge to provide a curved yarn engaging surface 2a. The other, and movable, set of fingers comprise small cylindrical members 8, one end of each of which is press fit into a passage in a shaft 19 rotatably' mounted on the base 6. Each member 8, which is preferably formed of tubular material and has its upper wall cut away for a portion of its length in order to reduce the weight thereof, extends into the space between adjacent fixed fingers 2. The shaft 10 is mounted for rotation about its axis by means of pivot screws 12 which thread through upstanding portions 6:: of the base 6 and engage pivot bearings 14 press fit into the ends of the shaft;

A pair of tension pads comprising lower and upper tongue-shaped elements 16 and 18, respectively, are mounted by means of a pin 19 on the base 6 between a part 6b of the base and a bifurcated cap 2! which is also mounted on the base 6 and extends over the part 6b. A curved tip 16a of pad 16 rests in a recess 60 ofthe part 6b of the base and a curved tip 13a enters a recess 20a in the cap 20. One end 22a of a light coiled spring 22, positioned between the furcations of the cap 20, bears against the upper surface of the pad l8 and the other end of the spring is welded to one end of a stiff wire 24 fixed to and movable with the shaft 10. The wire 24, which is mounted in a diametral hole in the shaft 10, is bent forwardly above the shaft so that its end overlies the tension pads. The wire 24 extends downwardly from the shaft '10 and supports at its lower end -a vane 26 which is Welded to the wire. The vane 26 is disposed within a dash pot 28 carried by, and preferably forming an integral p'artof, abracket 3G.

The bracket 30 has a vertical Wall portion secured in spaced relation to the base 6 by a pair of machine screws 34, carrying spacing collars 36. The upper end of the bracket 30 is inclined rearwa'rdly from the base 6 through a small angle and then is bent forwardly to form a horizontal platform 38 for support of the parts now to be described. Mounted in a slot 38a in the platform is a smooth bored externally threaded sleeve an opposite sides of which are cut away near the central part to fit within the slot 382: and t'o-preven't rotation and vertical reciprocation of the sleeve therein. A guide lock nut 42 having a knurled surface is threaded on the sleeve 40 above the platform 38 to secure the sleeve in any adjusted position along the slot 38a. A screw 44, the threads of which have been cut away along two opposite sides so as to reduce the thickness of the screw in one direction to substantially the width of slot 38a, is disposed within the sleeve 40 and held in adjusted position therein by means of an adjusting nut 46 that is threaded on the upper end of the screw. A spring wire '48 carried in a groove in the nut 46 and engaging the screwed through a slot 40a in the wall of the nut provides a de'tent action against a The lower end of screw 44 Thus the tension of the in through the cord 52 and wire 24 tends spring ac to rotate the shaft it in a direction to force the fingers 8 downwardly between the fixed yarn engaging elements 2 and to increase the pressure applied by the spring 22 to the upper tension pad 18.

In threading up the above-described device for regulating tension in travelling yarn, the shaft 19 is rotated, as by the thumb of an operator, against the tension of spring 50 to raise the fingers 8 and relieve the pressure on the upper tension pad 13. The yarn, indicated at Y in Fig. 2, is then slipped between the pads and between the fixed and movable sets of pins. Upon release of the shaft 10 by the operator, the angular position of the shaft will depend upon the tension in the yarn, which tends to raise the fingers 8, and upon the opposing tension of the spring 50, the latter depending upon the setting of the adjusting nut 46.

Raising of the fingers 8 as a result of increased yarn tension reduces the total angle of contact of the yarn with both the movable and fixed pins of the system and hence reduces the tension introduced into the yarn by the device in accordance with the exponential relation where To is input tension, T1 output tension, the coeificient of friction between the yarn and the surfaces in engagement therewith and a the total angle through which the yarn engages the surfaces. Raising of the fingers 8 under increase of yarn tension also reduces the pressure on the upper tension pad 18 and thereby further reduces the tension added by the device.

The spring 56, as heretofore indicated, provides the restoring force for the system. The normal or fixed bias tension in this spring may be adjusted by raising or lowering the screw 44 under control of the nut 45. The effective moment tending to rotate the shaft 10 as a result of the tension of the spring 50 may be adjusted by movement of the sleeve 4-0 along the slot 38a under control of the lock nut 42, the moment decreasing and therefore the sensitivity of the device increasing, as the sleeve is moved forwardly toward the open end of the slot. For any fixed adjusted position of the screw 44 and sleeve 40, the effective restoring force of the spring depends upon the product of the tension in the spring and the distance between the nylon cord 52 and the axis of the shaft 19. When the shaft has been rotated as a result of increase in tension in the yarn, spring 50 is extended and hence the tension thereof is increased. The distance, however, between the axis of shaft 10 and the cord '2 is decreased as will be apparent from Fig. 3 which shows in dotted lines the position of the parts when the fingers are raised. As the decrease in distance between the axis of the shaft and the cord with increase in separation of the fingers is proportionately much greater than the increase in tension in spring :73, the effective restoring force or torque acting on the shaft is substantially decreased. As shown in Figs. 3 and 4 the shaft 10 is cut away at 53 to permit freedom of movement of the cord 52 toward and away from the axis of the shaft. The torque decreases rapidly as the nylon cord 52 approaches the axis of shaft 19 and would become zero if the cord were permitted to pass through the axis of the shaft. In order to insure a slight residual restoring torque sufficient to overcome friction of the parts and to insure continued light contact of the fingers 8 with the yarn, the cut out portion 53 of the shaft 19 does not extend into the axis of the shaft.

Hunting or over control of the device under rapid changes of tension is avoided by damping the movement of the vane 26 in oil or other medium within the dash pot 28 as indicated in Fig. 3. The dash pot is preferably provided with a cover 28 which is slotted for accommodation of the wire 24 and cord 52.

In the embodiment of the invention illustrated in Figs. 5 to 8, inclusive, one set of fingers is fixed and comprises small plates 6% made of nonmagnetic material, such as brass or aluminum, defining spaces or sockets 61 between them. Each of the plates may be press fit or otherwise individually secured in channels 62 in a block member at, and is cut away and rounded along a part of its outer edge to provide a curved vertical yarn-enga ing channel 66; the other and movable set of fingers comprises small cylindrical pin members 63 made of tubular magnetically permeable material, such as iron or steel plated with chromium or like wear-resistant material, one end of each of which is press fit into a passage in a shaft 70 of nonmagnetic material and rotatably mounted on the base '72 which is also of nonmagnetic material; each pin member 63 has its on or wall cut away for a portion of its length in order to reduce the weight thereof and extends into a socket 61 between adjacent fixed fingers on. Block 64 is of netically permeable material and is affixed to base 72. by means of bolts 73 and 74 which are threaded through the base.

The shaft 70 is mounted for rotation about its axis by means of pivot screws at each end. Pivot screw 75 threads through a top laterally-extending portion 7! ol the base 72 and its pivot point engages pivot bcari' 78 which is press fit into the upper end of an extension 71 of the shaft 70. Pivot screw Jill is threaded through the base 82 of a basket-shaped support 33 attached to the lower end of base '72 and its pivot point engages pivot bearing 84 which is press fit into the lower end of the shaft 70. A pin 85, for manual rotation of the shaft '73 about its axis, is press fit into a passage in the shaft.

The support 83 comprises the base plate 82 and two vertical arms 36 and 87, generally wedge-shaped in cross section, and each with one rounded outer surface. "he arms are attached by bolts )0 and 91 to a threaded por' tion 88 dependent from and integral with the lower end of base 72. Threaded onto the portion 88 of base 7'2 is a sump 95 which serves as an oil reservoir.

The lower end of the shaft 7% is recessed at 96 for reception of a vane 97, which is afiixed to the shaft by a bolt 98 threaded through the shaft. The vane extends substantially to the inside wall of the sump 95 and its rotational movement in either direction is limited to a maximum arc of 100 by engagement with the vertical arms 86 and 87.

Press fit into a passage in a vertically-extending bracket portion Hi0 integral with the base 72 and at one side and at right angles to the laterally-extending portion 77 thereof is a shaft 101, and mounted upon the shaft is a pair of tension elements comprising inner and outer diskshaped elements 103 and 104, respectively. Disk 103 is immovably affixed to the face of bracket 180, while disk 104 is movable upon the shaft 101. A light coiled compression spring 1il7 engages at one end the outer face of the disk 104 and at the other end the inner edge of a triangular or wedge-shaped element 369. This element is reciprocably mounted in an axial slot 11 in the shaft 101. A guide lock not 112, having a hex surface, is threaded on the end of shaft 1411 beyond the element 109 and serves as a stop to secure that element in any adjusted maximum position along the slot, thereby regulating the pressure exerted by the spring 107 on disk M4.

The shaft 101 also is provided with an axial passage 114 extending from the slot to the other end of the shaft. The inner end of element 199 has a hole 117 therethrough for the reception of one end of a fine but strong cord 118 of nylon or the like, which extends through the axial passage 114 and through a diametral passage 120 in the extension 71 of shaft 70 and is fixed at its other end to the extension 71. The extension 71 ofthe shaft 70, which is preferably formed of hardened steel, is functionally mounted on the shaft so that" it may be turned on the shaft to regulate the windup of the cord 118 upon rotation of the shaft 70.

Also attached to one side of the base 72 by bolts 73 and 74 threaded therein are an upstanding and laterallyextending L-shaped bracket support 124 of non-magnetic material and a block 125 of magnetically permeable ma terial. One face of the block 125 is recessed at 126 to receive the shaft 70. The bracket 124 serves as a support for a magnet assembly containing two magnets 127 and'128 held on a threaded nut 139 of brass or like nonmagnetic material by the vertical brass clamp screws 131 and 132 and brass washers 133 and 134. Themagnets are of horseshoe or other shape and of such a size that one pole or arm 140 thereof abuts block 64 and arm 141 thereof abuts the block 64 and the other pole or arm, only one of which, indicated at 141, appears in the drawing, abuts the block 125. In consequence, blocks 64 and 125 are yokes in the magnetic circuit and when the pins or fingers 68 afiixed to shaft 70 are within the sockets 61, they are within the field of force exerted by yoke 64. If desired, a pair of bar magnets might be used in place of a horseshoe magnet.

The nut 130 is threaded on a screw shaft 135 which passes through the bracket 124 and is rotated by the brass knob 136. A thrust ring 138 of steeLbrass or other metal such as a Waldes snap ring, is fixed in an annular groove in the screw shaft 135 and prevents the screw shaft from backing out of bracket 124. The magnets are slidable laterally of the yoke pieces 64 and 125 to adjust the magnetic force exerted upon the pins 68.

In threading up the above-described device for regulating tension in travelling yarn, the operator, by means of the pin 85, rotates the shaft '70 against the force of the yoke 64 so as to separate the fixed and movable sets of pins 60 and 68, respectively. The yarn, indicated at Y in Fig. 7 is then slipped between the tension disks 103 and 104 and between the fixed and movable sets of pins into the yarn-engaging channel 66. The operator then releases the shaft 7%, and, thereafter the shaft 79 will assume'an angular position dependent upon the tension in the yarn, an increase in tension tending to separate the plates 60 and pins 68.

Rotation of the shaft 70 in a direction to move the pins 68 away from the plates 60 resulting from an increase in yarn tension reduces the total angle of contactof the yarn with both the movable pins 68 and the fixed plates 60 of the system, as in the embodiment of the invention illustrated in Figs. 1 to 4. Rotation of the shaft 70 in a direction to move the pins 68 away from the plates 64) reduces the angle of Wrap of the nylon cord 113 on the shaft extension 71 and thus permits the spring base element 169 secured to the other end of the cord to be moved toward the nut 112 under the influence of the spring 107. The pressure of outer tension disk 104 upon the inner tension disk 103, and the tension added thereby to the yarn is thus reduced.

The magnets 127 and 128 provide the restoring force for the system. The normal or fixed bias force exerted by the magnets may be adjusted to any degree by sliding the magnets laterally of the yoke pieces 64 and 125 by rotating the shaft 135 with the knob 136, so that the magnetic force in the yoke pieces is reduced or increased. When the shaft 70 has been rotated in a clockwise direction as a result of increase in tension in the yarn, the distance between the pins 68 and the yoke 6" is increased, as will be apparent from Fig. 7, which shows in dotted lines the position of the parts when the shaft is rotated, and thus the effective restoring force or torque acting on the pins 68 and shaft 70 is substantially decreased. In order to insure continued light contact of the fingers 63 with the yarn under increase in tension, the cut-out portions 66 in the plates 68 place the yarn path at a point less than 45 along the arc of rotation described by the pins 68 from the block 64, thus providing a margin of rotation during which some residual magnetic force is still exerted upon the pins 68.

Hunting or over control of the device under rapid changes in tension are avoided by damping the movement of the vane 97 in oil or other medium within the dash pot as indicated in Figs. 5 and 6.

From the above description of two embodiments of the invention it will be apparent that the new devices meet all the requirements for sensitive, rapid acting and yet stable tension regulators. In each of the described embodiments of the invention the construction insures decreasing restoring force with increasing yarn tension and hence the tension introduced into the yarn may be made extremely small when the input tension exceeds the working range of the device, that is, when the input tension exceeds the desired output tension. In the device of Figs. 1 to 4, the restoring force of a spring is decreased by decrease in moment arm; in that of Figs. 5 to 8, the restoring force of the magnet is decreased by increase in air gap. Within the working range of each device, that is for all input tensionsbelow the desired output tension, the device maintains the output tension at that desired by introducing sufficient tension to compensate for the difference between the input tension and the desired output tension. Devices constructed in accordance with the invention, while of general utility in controlling yarn tension, have been found particularly valuable in controlling the tension in yarn during quill winding where velocity changes of the yarn are substantially two and half to one. Using the new device as a regulator, non-sloughing quills have been successfully wound at 12 to 15 grams whereas with the same winding machine but with ordinary disk type tension devices, the tension ranges from 25 to 30 grams during quill winding.

The invention has now been described with reference to the preferred embodiments thereof. Obviously various changes could be made in the particular constructions illustrated and described and parts could be omitted without departing from the spirit of the invention or from the scope of the appended claims. For example, it is not essential to the operation of the device that tension pads or disks either under variable, as described, or fixed tension be incorporated in the device. Tension pads or disks are preferably provided, however, particularly when the yarn is under very low tension prior to delivery to the device, as the fixed and movable fingers of the device act as a tension multiplier and the tension pads, in the case of low initial yarn tension, provide a tension to be multpilied. In any event the tension introduced by the pads or equivalent pinch type of tension device should preferably be small as compared to that introduced by the fixed and movable fingers, the ratio being of the order of one to ten. This ratio will depend in part upon the number of fixed and movableffingers of the device. In the illustrated embodiments of the invention there are four or five movable and five or six fixed fingers; obviously a lesser or a greater number could be employed as desired. Broadly speaking, a device having but one fixed and one movable finger would be satisfactory for applications Where large variations in input tension are not encountered, and such device is within the scope of the invention.

The following is claimed:

1. A compensator operative in all positions of orientationfor maintaining more uniform the tension in traveling oscillation of the shaft, and a magnet at least one pole of which is disposed adjacent said movable pin members whereby said members are magnetically attracted toward movement into the spaces between said fixed elements so that when filamentary material is threaded between said fixed elements and said pin members the force of magnetic attraction on said pin members acts in opposition to the tension in the material to increase the angle of contact of the material with said fixed elements and said pin members, and said force progressively decreases as the total angle of contact of the material with the surface of said pin members decreases.

2. The compensator according to claim 1 wherein the portion of the base member having the spaced material engaging elements fixed thereon is made of magnetizable material and constitutes a pole piece against which one pole of said magnet is disposed, and means for adjusting the position of said magnet with respect to said pole piece to vary the force of magnetic attraction on said pin members.

3. The compensator according to claim 1 wherein said base member has a cupped member attached thereto for retaining a damping liquid, and said shaft has an extension projecting into said cupped member and is provided with a damping vane immersed in said liquid for damping the oscillatory movement of said shaft.

4. The compensator according to claim 1 wherein said base member has an elongated member secured thereto and disposed at an angle to the axis of said shaft, said elongated member having a slot in one end and a longitudinal passage therethrough extending from said slot to the other end thereof, adjustable means slidably mounted in said slot. a pair of disks carried by said elongated member and adapted to engage the filamentary material therebetween for inserting tension in the filamentary material prior to contact thereof with the fixed elements and movable pin members, one of said disks being mounted for limited movement toward and away from the other, spring means mounted on said elongated member between said adjustable means and said last-named disk to urge said disk toward the other disk, and a flexible cord disposed in the passage of said elongated member and secured to said adjustable means and said shaft to operatively connect said spring means and said shaft to vary the tension supplied by said disks in accordance with variations in. tension supplied by said fixed elements and said pin members.

5. A device for tensioning a lengthwise moving thread comprising a plurality of fixed members in spaced alignment along its path, movable members spaced in alternation with said fixed members, said fixed and movable members being adapted to tension said thread by rubbing contact therewith as the thread is drawn past and alternately about said fixed and movable members in a partial Wrap about each, and means urging said movable members with a variable force transversely of the thread path to increase the angle of each said partial wrap, said force increasing as said movable members move in the direction of said force and decreasing as they move in the opposite direction, said movable members and said urging means being substantially devoid of operative inertia.

6. A device for tensioning a lengthwise moving thread comprising a plurality of fixed members in spaced alignment along the thread path, movable members spaced in alternation with said fixed members, said fixed and movable members being adapted to tension said thread by frictional contact therewith as the thread is drawn past and alternately about said fixed and movable members in a partial wrap about each, and resilient means urging said movable members transversely of the thread path so as to increase the angle of each said partial wrap, said resilient means acting through an effective lever arm of increasing length as the degree of wrap increases whereby the force urging said movable members transversely of the thread path increases as the degree of wrap increases, said movable members and said resilient means being substantially devoid of operative inertia.

7. A tension compensator for yarn comprising in combination a base member having spaced yarn engaging elements fixed thereon, a shaft oscillatably mounted on said base member and carrying a plurality of rounded pin members, the axes of said pin members being in the same plane and the pin members being spaced along the shaft so as to alternate with the fixed elements and to be movable into and out of the spaces between the fixed elements with oscillation of the shaft, a substantially rigid elongated member secured to said shaft at an angle to the longitudinal axis thereof, and spring means fixed at one end and having its other end coupled to said rigid elongated member to urge rotation of said shaft and movement of said pin members between said fixed elements so that when filamentary material is threaded between said fixed elements and said pin members, said springs acts, in opposition to the tension in the material, to increase the angle of contact of the material with said fixed elements and with said pin members, the coupling between said spring and said rigid elongated member being such that said spring acts through a lever arm of progressively diminishing effective length as the total angle of contact of the material with the surface of said pin members increases.

8. A tension compensator according to claim 7 including a part carried by said base member and forming a chamber adapted to contain damping fluid, and a vane operatively connected to said shaft and disposed within said chamber.

9. A tension compensator according to claim 7 including support means secured to said base member and having a part spaced therefrom to form a platform, adjustable means for securing one end of said spring memer to said platform, and a flexible cord-like member connecting the other end of said spring with an end of said rigid elongated member.

10. A tension compensator according to claim 9 wherein said platform is provided with a slot generally parallel to the axis of said pin members, said adjustable means being slidable in said slot for varying the elfective turning moment of said spring on said shaft.

ll. A tension compensator according to claim 10 wherein said adjustable means includes an externally threaded tubular element non-rotatably mounted in said slot, 2. member threaded on said tubular member for loci-:- ing the same in any adjusted position along the slot, a rod-like member extending through said tubular member and secured at its lower end to said spring, and means for adjusting the vertical position of said rod-like member for adjusting the tension in said spring. 12. A tension compensator according to claim 7 including a pinch tensioner to pretension said filamentary material prior to its being passed between said fixed elements and said pin members.

13. A tension compensator according to claim 12 including means for varying the tension imparted to the material by said pinch tensioner in accordance with the total angle through which the material contacts said pin members and said fixed element.

14. A tension compensator for a moving length of yarn comprising in combination a plurality of fixed yarn engaging elements in spaced alignment along the yarn path, movable yarn engaging elements spaced in alternation with said fixed elements, said movable yarn engaging elements being carried by an oscillatory member and movable into and out of the spaces between the fixed yarn engaging elements upon oscillation of said member, and biasing means, including a spring and means connecting said spring to said oscillatory member, to urge movement of said movable yarn engaging elements between said fixed yarn engaging elements so that when filamentary material is threaded between said fixed and that said spring acts through an effective lever arm of variable length to urge said movable elements between said fixed elements with increasing force as the angle of contact of said filamentary material with said fixed and movable elements increases, said connecting means providing an effective lever arm of substantially zero length when the positional relationship of said movable elements with respect to said fixed elements is approximately such that the angle of contact of said filamentary material with said fixed and movable elements approaches zero degrees.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Great Britain Oct. 29, 

